 MD 30 was widened from Hampstead south to the Baltimore–Carroll county line in 1938 with a pair of -wide macadam shoulders, expanding the road's width to .MD 30 was relocated in a few spots, widened, and resurfaced from the county line north to Manchester in 1950, from the county line south to the north end of the Glen Morris relocation in 1951 and 1952, and from Manchester north to the Pennsylvania state line in 1953 and 1954.A MD 30 bypass of Hampstead has been contemplated since the 1940s and planned since at least 1960.